Method of applying a wear-resistant layer to a surface of a downhole component

Abstract

A method of applying a wear-resistant material to a surface of a downhole component for use in subsurface drilling comprises forming a plurality of bearing elements, applying a layer of an electrically conductive, less hard material to each bearing element, and then bonding each bearing element to the surface of the component by welding or brazing to the surface of the component a part of the surface of the bearing element which comprises said less hard material, wherein the layer is of thickness greater than 0.05mm.

What is claimed is:  
     
         1 . A method of applying a wear-resistant material to a surface of a downhole component, the method comprising forming a plurality of bearing elements, applying a layer of an electrically conductive, less hard material to each bearing element, and then bonding each bearing element to the surface of the component using one of a welding process and a brazing process to bond to the surface of the component a part of the surface of the bearing element which comprises said less hard material, wherein the layer is of thickness greater than about 0.05mm.  
     
     
         2 . The method of    claim 1   , wherein each bearing element comprises a body of thermally stable polycrystalline diamond.  
     
     
         3 . The method of    claim 1   , wherein the layer of less hard material comprises a coating applied to at least part of each bearing element.  
     
     
         4 . The method of    claim 1   , wherein the layer of less hard material is of high electrically conductivity.  
     
     
         5 . The method of    claim 4   , wherein the layer of less hard material is formed from a material selected from a group consisting of nickel and alloys containing nickel.  
     
     
         6 . The method of    claim 1   , wherein each bearing element is bonded to the surface using an electrical resistance welding technique.  
     
     
         7 . The method of    claim 1   , further comprising applying a layer of a carbide forming metal to each bearing element prior to the application of the layer of less hard material thereto.  
     
     
         8 . The method of    claim 1   , wherein the layer of less hard material is of thickness of between about 0.1mm and about 0.3mm.  
     
     
         9 . The method of    claim 8   , wherein the layer of less hard material is of thickness of between about 0.15mm and about 0.25mm.  
     
     
         10 . The method of    claim 9   , wherein the layer of less hard material is of thickness of between about 0.15mm and about 0.2mm.  
     
     
         11 . The method of    claim 1   , further comprising a step of applying a layer of a hardfacing material over and around the bearing elements.  
     
     
         12 . A downhole component having a surface to which a plurality of bearing elements are bonded, each bearing element having previously had a layer of a less hard, electrically conductive material applied thereto, the layer of less hard material having a thickness greater than about 0.05mm.  
     
     
         13 . The downhole component of    claim 12   , and shaped to act as one of a roller cone bit, a fixed cutter bit, a stabilizer unit and a bias unit.  
     
     
         14 . The downhole component of    claim 12   , wherein each bearing element comprises a body of thermally stable polycrystalline diamond.  
     
     
         15 . The downhole component of    claim 12   , wherein the layer of less hard material comprises a coating applied to at least part of each bearing element.  
     
     
         16 . The downhole component of    claim 12   , wherein the layer of less hard material is of high electrically conductivity.  
     
     
         17 . A method as claimed in    claim 16   , wherein the layer of less hard material is formed from a material selected from a group consisting of nickel and alloys containing nickel.  
     
     
         18 . The downhole component of    claim 12   , wherein each bearing element is bonded to the surface using an electrical resistance welding technique.  
     
     
         19 . The downhole component of    claim 12   , wherein the layer of less hard material is of thickness of between about 0.1mm and about 0.3mm.  
     
     
         20 . The downhole component of    claim 19   , wherein the layer of less hard material is of thickness of between about 0.15mm and about 0.25mm.  
     
     
         21 . The downhole component of    claim 20   , wherein the layer of less hard material is of thickness of between about 0.15mm and about 0.2mm.